Does the game use the number pad this way throughout? I ask because I have a compact keyboard that doesn't have a number pad, and I'm wondering if this is going to be an issue.
As stated above, some of the later games will allow the use of a mouse. For all the games, check the quick reference card PDF and it will tell you what keys are used for each game. If you haven't bought the collection yet, let me know and I can check my QRCs.
EDIT: Just looked through them and all list the number pad for movement keys. A number also list native joystick and mouse support. Given that the keyboard controls are fairly consistant across the gold box games, I don't see why something like the DosBox mapper or Xpadder couldn't make a workable profile for any of the games. Keys most often used would be the numpad keys for movement, the Enter key for selections and the ESC key for cancel/quit.
EDIT2: Well, unfortunately, trying this with Pool of Radiance doesn't work very well. The game requires a number of keyboard inputs that in later games were selected with a cursor. Also, the mapper in DosBox doesn't support mapping diagonals to the hat-switch on an Xbox controller (the D-pad). Haven't tried mapping to the axis, but since the game requires 8 individual direction inputs, I don't think it will work with the built-in mapper.
I know that Pinnacle/Padstarr will map an 8-direction dpad, so that could be an option. Xpadder should as well, and I think that's going to be the best bet for games that allow selection with a cursor. Those games may already have built-in joystick support, so it may be a moot point. Pool of Radiance (and I suspect Curse of the Azure Bonds) require you to select most menu items with a keyboard shortcut rather than the numpad, so it might be very difficult to map to a controller.
EDIT Final: The first game to support Joystick controls is Secret of the Silver Blades. It requires the joystick to be plugged in and then enabled in the menu. Once enabled it runs through a quick calibration and then works. However, the joystick controls are extremely sensitive, so you'll need to fiddle with the settings in order to get it working to some degree of usability. Most of these games will also work with the standard cursor keys for menus and cardinal directions in combat. Diagonal movement in combat still requires the numpad keys though.
Hope this helps. =)